Delay and related circuits are generally known in the art. Examples of such circuits are as follows:
Japanese Patent No. 60-33732 discloses a delay circuit whose delay time is stable against power supply variations and temperature fluctuations. This circuit varies an injector current from a constant current supply (an operational amplifier) to obtain changes in the delay time of the circuit
U.S. Pat. No. 3,346,746 discloses a monostable multivibrator triggered by an OR-gate which receives a plurality of inputs. In addition, the pulse time of the multivibrator is in part controlled by a variable timing network in response to the particular input which input triggered the multivibrator.
U.S. Pat. No. 3,753,012 discloses a time delay generator which provides a plurality of precise time delays following a trigger action.
U.S. Pat. No. 3,675,133 discloses an apparatus for independently varying, by preselected amounts, the position of pulse edges by the use of a plurality of variable delay means.
U.S. Pat. No. 3,558,924 discloses a circuit having a plurality of input signals with corresponding time-delayed independent output signals.
Other references which are related to the general field of delay circuits are: U.S. Pat. Nos. 2,964,708, 3,102,208, 4,140,927, 4,587,441 and 4,638,188, and Japanese Patent Nos. 57-99029 and 57-131126.
In designing delay circuits, it is important that the delay characteristics of the circuit be as accurate as possible.
Further, it is necessary to consider process tolerances, temperature differentials and changes in the power supply of the delay circuit, all of which are factors in the reliability or accuracy of a delay circuit.